kirra-docs
Surface Boolean & CSG Operations
Kirra provides tools for combining, subtracting, and intersecting surfaces. These operations enable pit shell manipulation, surface clipping, and design surface combination directly within the application.
Building triangulations during a surface boolean operation – splitting triangles along the intersection boundary.
The completed solid after merging the kept regions from a boolean operation.
Surface Boolean
Performs boolean operations (Union, Difference, Intersection) on two triangulated surfaces.
How It Works
- Select two surfaces (A and B) in the dialog
- Kirra finds where the surfaces intersect
- Triangles along the intersection boundary are split
- Each region is classified as above, below, or outside the other surface
- Colour-coded preview shows the regions
- Toggle which regions to keep
- Click Merge to combine the kept regions into a new surface
Operations
| Operation | Result |
|---|---|
| Union | Combined volume of both surfaces |
| Difference | Surface A minus the volume of B |
| Intersection | Only the overlapping region |
Cleanup Pipeline
After merging, Kirra runs a configurable cleanup pipeline:
| Step | Description |
|---|---|
| Seam Deduplication | Merges vertices at the intersection boundary |
| Weld | Merges nearby vertices within snap tolerance |
| Degenerate Removal | Removes zero-area triangles |
| Sliver Removal | Removes extremely thin triangles (optional) |
| Crossing Cleanup | Removes self-intersecting triangles (optional) |
| Overlap Removal | Removes duplicate triangles with opposing normals (optional) |
| Stitch | Bridges unpaired boundary edges (optional) |
Access
Click the Surface Boolean button in the Surface toolbar. Requires at least 2 loaded surfaces.
Solid CSG
Constructive Solid Geometry (CSG) operations on closed watertight 3D solids. Supports union, subtract, and intersect operations.
Unlike the surface boolean (which works on open triangulated surfaces), Solid CSG requires both meshes to be closed solids.
Access
Click the Solid CSG button in the Surface toolbar. Requires at least 2 loaded closed surfaces.
Surface Intersection
Computes the intersection lines where two surfaces meet, producing KAD polyline entities.
Configuration
| Parameter | Default | Description |
|---|---|---|
| Vertex Spacing | 1.0 m | Simplification tolerance (0 = keep all vertices) |
| Close Polygons | true | Create closed polylines |
| Colour | Yellow | Colour of result polylines |
| Line Width | 3 | Thickness of output lines |
Access
Click the Surface Intersection button in the Surface toolbar. Requires at least 2 loaded surfaces.
Extrude KAD to Solid
Extrudes a closed KAD polygon vertically to create a 3D solid mesh. Useful for creating pit shells, bench outlines, or exclusion zone volumes from 2D design boundaries.
Access
Click the Extrude KAD button in the Surface toolbar. Requires at least 1 closed KAD polygon entity.
KAD Boolean
Performs 2D boolean operations on KAD polygon entities (union, difference, intersection). Useful for combining or subtracting design boundaries.
Access
Click the KAD Boolean button in the Surface toolbar. Requires at least 2 KAD polygon entities.
Section Plane
Creates a cross-section cutting plane through loaded surfaces for visualisation of subsurface geometry and design verification.
Access
Click the Section Plane button in the Surface toolbar. Requires at least 1 loaded surface.